Development of an in vivo tumor-mimic model for learning radiofrequency ablation

J Gastrointest Surg. 2000 Nov-Dec;4(6):620-5. doi: 10.1016/s1091-255x(00)80112-2.

Abstract

Radiofrequency ablation requires accurate probe placement using ultrasound guidance. The purpose of this study was to develop an in vivo tumor-mimic model for learning open and laparoscopic radiofrequency ablation. Tumor-mimics were created in ex vivo porcine livers by injecting a mixture of 3% agarose, 3% cellulose, 7% glycerol, and 0.05% methylene blue, which formed 1 cm hyperechoic, discrete lesions on ultrasound. Open and laparoscopic (using a box-trainer) ablation techniques were practiced. In vivo experiments were then conducted in 10 pigs. Three tumor-mimics were created in each animal using a laparoscopic approach. Lesions were characterized sonographically, ablated using an open (n = 5) or laparoscopic (n = 5) approach, and examined pathologically. An ablation in normal liver tissue was performed as a control. Tissue impedance was recorded. Target creation took 81 minutes per animal and 96% of injections were successful. Tissue impedance (48.8 +/- 5.8 vs. 49.6 +/- 5.4) and ablation size (25.1 +/- 3.4 vs. 24.3 +/- 5.1) were not significantly different for controls (n = 8) and tumor-mimics (n = 26), respectively. One animal died of a pulmonary embolism following injection of agarose into a hepatic vein. The agarose-based tissue-mimic creates realistic sonographic targets for learning ultrasound-guided open and laparoscopic radiofrequency ablation in an in vivo model.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Catheter Ablation / instrumentation
  • Catheter Ablation / methods*
  • Disease Models, Animal
  • Equipment Design
  • Equipment Safety
  • General Surgery / education*
  • In Vitro Techniques
  • Liver Neoplasms / diagnostic imaging
  • Liver Neoplasms / surgery*
  • Models, Anatomic*
  • Sensitivity and Specificity
  • Swine
  • Texas
  • Ultrasonography